Mitotic spindles revisited - new insights from 3D electron microscopy.

The mitotic spindle is a complex three-dimensional (3D) apparatus that functions to ensure the faithful segregation of chromosomes during cell division. Our current understanding of spindle architecture is mainly based on a plethora of information derived from light microscopy with rather few insights about spindle ultrastructure obtained from electron microscopy. In this Review, we will provide insights into the history of imaging of mitotic spindles and highlight recent technological advances in electron tomography and data processing, which have delivered detailed 3D reconstructions of mitotic spindles in the early embryo of the nematode Caenorhabditis elegans Tomographic reconstructions provide novel views on spindles and will enable us to revisit and address long-standing questions in the field of mitosis.